UNIV_LIKELY()/UNIV_UNLIKELY() hints are supposed to improve branch prediction.
Currently, they're expected to work only if cond evaluates to TRUE or FALSE.
However there're a few conditions that may evaluate to different values, e.g.:
page/page0zip.cc: if (UNIV_LIKELY(c_stream->avail_in)) {
page/page0zip.cc: if (UNIV_LIKELY(c_stream->avail_in)) {
dict/dict0mem.cc: if (UNIV_LIKELY(i) && UNIV_UNLIKELY(!table->col_names)) {
Fixed these conditions so that they evaluate TRUE/FALSE.
Analysis: MySQL table definition contains also virtual columns. Similarly,
index fielnr references MySQL table fields. However, InnoDB table definition
does not contain virtual columns. Therefore, when matching MySQL key fieldnr
we need to use actual column name to find out referenced InnoDB dictionary
column name.
Fix: Add new function to match MySQL index key columns to InnoDB dictionary.
when created FK
Analysis: Table name is on filename charset but foreign key
identifiers are not. This lead incorrect foreign key
identifier number to be used.
Fix: Convert foreign key identifier to filename charset before
comparing it to table name when largest foreign key identifier
number is resolved.
Analysis: after a red-black-tree lookup we use node withouth
checking did lookup succeed or not. This lead to situation
where NULL-pointer was used.
Fix: Add additional check that found node from red-back-tree
is valid.
Problem:
This is a coding mistake during error handling. When the specified foreign
key constraint is wrong because of data type mismatch, the resulting
foreign key object will not have valid foreign->id (it will be NULL.)
Solution:
While removing the foreign key object from dictionary cache during error
handling, ensure that foreign->id is not null before using it.
rb#8204 approved by Sunny.
causes server crash
Analysis: If wrong data types used on foreign constraint there
was possibility that foreign->id is NULL when incorrect
foreign constraint was removed from the dictionary cache.
Fix: Add guard foreign->id != NULL before trying to lookup
or remove the foreign constraint from dictionary cache.
Tested using user database where problem was repeatable.
Merge Facebook commit 154c579b828a60722a7d9477fc61868c07453d08
and e8f0052f9b112dc786bf9b957ed5b16a5749f7fd authored
by Steaphan Greene from https://github.com/facebook/mysql-5.6
Optimize prefix index queries to skip cluster index lookup when possible.
Currently InnoDB will always fetch the clustered index (primary key
index) for all prefix columns in an index, even when the value of a
particular record is smaller than the prefix length. This change
optimizes that case to use the record from the secondary index and avoid
the extra lookup.
Also adds two status vars that track how effective this is:
innodb_secondary_index_triggered_cluster_reads:
Times secondary index lookup triggered cluster lookup.
innodb_secondary_index_triggered_cluster_reads_avoided:
Times prefix optimization avoided triggering cluster lookup.
Problem:
In the function dict_foreign_remove_from_cache(), the rb tree was updated
without actually verifying whether the given foreign key object is there in the
rb tree or not. There can be an existing foreign key object with the same id
in the rb tree, which must not be removed. Such a scenario comes when an
attempt is made to add a foreign key object with a duplicate identifier.
Solution:
When the foreign key object is removed from the dictionary cache, ensure
that the foreign key object removed from the rbt is the correct one.
rb#7168 approved by Jimmy and Marko.
Problem:
In the function dict_foreign_remove_from_cache(), the rb tree was updated
without actually verifying whether the given foreign key object is there in the
rb tree or not. There can be an existing foreign key object with the same id
in the rb tree, which must not be removed. Such a scenario comes when an
attempt is made to add a foreign key object with a duplicate identifier.
Solution:
When the foreign key object is removed from the dictionary cache, ensure
that the foreign key object removed from the rbt is the correct one.
rb#7168 approved by Jimmy and Marko.
dict_set_corrupted(): Use the canonical way of searching for
less-than-equal (PAGE_CUR_LE) and then checking low_match.
The code that was introduced in MySQL 5.5.17 in
Bug#11830883 SUPPORT "CORRUPTED" BIT FOR INNODB TABLES AND INDEXES
could position the cursor on the page supremum, and then attempt
to overwrite non-existing 7th field of the 1-field supremum record.
Approved by Jimmy Yang
dict_set_corrupted(): Use the canonical way of searching for
less-than-equal (PAGE_CUR_LE) and then checking low_match.
The code that was introduced in MySQL 5.5.17 in
Bug#11830883 SUPPORT "CORRUPTED" BIT FOR INNODB TABLES AND INDEXES
could position the cursor on the page supremum, and then attempt
to overwrite non-existing 7th field of the 1-field supremum record.
Approved by Jimmy Yang
Merged Facebook commit dd2d11be7aaf3be270e740fb95cbc4eacb52f4d7
authored by Rongrong Zhong from https://github.com/facebook/mysql-5.6
This fixes MySQL Bug #68220 innodb_rows_updated is misleading on slave
http://bugs.mysql.com/bug.php?id=68220
Added innodb_system_rows_read/inserted/updated/deleted counters
that are the equivalent of innodb_rows_* but that only account for
changes made to system databases (mysql, information_schame and
preformance_schema). These counters will be used on slaves to
differentiated the updates made on system databases from those made on
user databases.
innodb_rows_* status counters are not updated when innodb_system_rows_*
are updated.
dd2d11be7a
When UNIV_INTERN is missing in built-in XtraDB, this causes the
innodb_plugin to call the XtraDB version of the function instead
of its own (seen in --embedded-server test failure in Buildbot).
This in turn causes bad things to happen in case of difference
between XtranDB and innodb_plugin.
Problem:
Creation of a table fails when innodb_strict_mode is enabled, but the same
table is created without any warning when innodb_strict_mode is enabled.
Solution:
If creation of a table fails with an error when innodb_strict_mode is
enabled, it must issue a warning when innodb_strict_mode is disabled.
rb#6723 approved by Krunal.
Problem:
Creation of a table fails when innodb_strict_mode is enabled, but the same
table is created without any warning when innodb_strict_mode is enabled.
Solution:
If creation of a table fails with an error when innodb_strict_mode is
enabled, it must issue a warning when innodb_strict_mode is disabled.
rb#6723 approved by Krunal.
Merged lp:maria/maria-10.0-galera up to revision 3880.
Added a new functions to handler API to forcefully abort_transaction,
producing fake_trx_id, get_checkpoint and set_checkpoint for XA. These
were added for future possiblity to add more storage engines that
could use galera replication.
Merged lp:maria/maria-10.0-galera up to revision 3879.
Added a new functions to handler API to forcefully abort_transaction,
producing fake_trx_id, get_checkpoint and set_checkpoint for XA. These
were added for future possiblity to add more storage engines that
could use galera replication.
Problem:
We maintain two rb trees in each dict_table_t. The foreign_rbt must be in
sync with foreign_list. The referenced_rbt must be in sync with
referenced_list. There is one function which checks this consistency and it
failed, resulting in an assert failure.
The root cause of the problem was identified that the search order was
lost in the referenced_rbt. This is because while renaming the table,
we didn't not refresh this referenced_rbt.
Solution:
When a foreign key is renamed, we must delete and re-insert into both
foreign_rbt and referenced_rbt.
rb#6412 approved by Jimmy.
Problem:
We maintain two rb trees in each dict_table_t. The foreign_rbt must be in
sync with foreign_list. The referenced_rbt must be in sync with
referenced_list. There is one function which checks this consistency and it
failed, resulting in an assert failure.
The root cause of the problem was identified that the search order was
lost in the referenced_rbt. This is because while renaming the table,
we didn't not refresh this referenced_rbt.
Solution:
When a foreign key is renamed, we must delete and re-insert into both
foreign_rbt and referenced_rbt.
rb#6412 approved by Jimmy.
~40% bugfixed(*) applied
~40$ bugfixed reverted (incorrect or we're not buggy)
~20% bugfixed applied, despite us being not buggy
(*) only changes in the server code, e.g. not cmakefiles
IN RECOVERY
During redo log processing, the data dictionary is not available. We should
check it in dict_find_table_by_space() to prevent SEGV error.
rb#5678, approved by Jimmy.
IN RECOVERY
During redo log processing, the data dictionary is not available. We should
check it in dict_find_table_by_space() to prevent SEGV error.
rb#5678, approved by Jimmy.
If mysql.innodb_table_stats or mysql.innodb_index_stats is not found or has
unexpected structure output that error only once and no other error for
every table trying to use them. If they do exists, then print fetch or
recalculation errors only once / table or index.
SLOW/CRASHES SEMAPHORE
Problem:
There are 2 lakh tables - fk_000001, fk_000002 ... fk_200000. All of them
are related to the same parent_table through a foreign key constraint.
When the parent_table is loaded into the dictionary cache, all the child table
will also be loaded. This is taking lot of time. Since this operation happens
when the dictionary latch is taken, the scenario leads to "long semaphore wait"
situation and the server gets killed.
Analysis:
A simple performance analysis showed that the slowness is because of the
dict_foreign_find() function. It does a linear search on two linked list
table->foreign_list and table->referenced_list, looking for a particular
foreign key object based on foreign->id as the key. This is called two
times for each foreign key object.
Solution:
Introduce a rb tree in table->foreign_rbt and table->referenced_rbt, which
are some sort of index on table->foreign_list and table->referenced_list
respectively, using foreign->id as the key. These rbt structures will be
solely used by dict_foreign_find().
rb#5599 approved by Vasil
